As the latest HQCA report on obesity in Alberta released this week, the substantial population burden of overweight and obesity (now affecting 6 in 10 Albertans) is a significant driver of health care costs in the province. In the US, this increased health care cost for adult obesity is estimated at around $3,508 per individual with a BMI greater than 30 for a total of well over US$ 300 billion per year.
However, as highlighted in a recent article by John Cawley and colleagues in PharmacoEconomics, health care costs are not equally distributed across all people living with increased body weight – rather, obesity related health care costs rise exponentially with increasing BMI levels (i.e. at the extremes of BMI).
Thus, the greatest health care savings for individual patients can be expected in those living with severe obesity.
To illustrate this, the researchers used data from the US Medical Expenditure Panel Survey from 2000-2010 (n=41,435), to calculate the potential annual savings in health care costs (in US $ in the US health care system), for various reductions in body weight in individuals with BMI levels ranging from 30 kg/m2 to 45 kg/m2.
Thus, for e.g. the annual cost savings with a 5% reduction in body weight for someone with a BMI of 30 kg/m2 amounted to a mere $69 per year.
This figure, however, increased exponentially for people with higher BMIs, increasing to $528, $2,137, and $10,030 in an individual with a BMI of 35, 40, and 45 kg/m2, respectively (these figures were somewhat higher, when the individual also has diabetes).
Thus, while treating obesity to achieve a 5% reduction in body weight in someone with a BMI of 30 kg/m2 may never be “cost-effective”, the same amount of weight loss in someone with more extreme obesity, would likely pay for itself or even lead to significant savings.
Because the impact of obesity on mental and physical health, life-expectancy and quality of life is also greatest at higher levels of BMI, one could also make a strong ethical argument for singling out these individuals for priority treatment in the health care system.
Obviously, as readers should be aware, BMI is at best a crude measure for health – a more precise assessment would have used more sophisticated staging systems like the Edmonton Obesity Staging System to calculate individual risk and benefits. However, we should remember that at a population level BMI does function moderately well as an indicator of obesity related risk (although not in individual patients).
This analysis has important consequences both for population and individuals approaches to obesity.
Although the population burden of obesity lies in the middle of the BMI bell curve, and shifting this ever so slightly can move a substantial number of people living with overweight or obesity to a BMI that lies below the current cut-offs, such a change may have little influence on the overall health care costs of obesity, as these live in the extremes.
Thus, using the above numbers in a crude back-of-the-envelope calculation, to save $1,000,0000 per year in health care costs, one would have to lower BMI by 5% in about 14,500 people living with a BMI of 30 kg/m2 compared to only 100 people with a BMI of 45 kg/m2 – a much more manageable problem.
This is why it is harder to make a cost-savings argument for addressing obesity at a population level rather than focussing on those living with more severe obesity, unless such population measures can also substantially help lower the BMI of the latter.
Unfortunately, current population trends show that while rates of overweight and mild obesity appear to be levelling off (thank perhaps in part to population health measures), severe obesity continues to increase at alarming rates.
This is why a greater focus on finding and delivering better treatments to those living with severe obesity, including those that can only offer modest reductions in BMI, has to be the main priority of any health care system seeking to reduce obesity related health care costs.
To conclude this brief series on our new exhaustive review of the putative health benefits of long-term weight-loss maintenance, published in Annual Reviews of Nutrition, here is the summary paragraph of our findings:
“Obesity is well recognized as a risk factor for a wide range of health issues affecting virtually every organ system. There is now considerable evidence that intentional weight loss is associated with clinically relevant benefits for the majority of these health issues. However, the degree of weight loss that must be achieved and sustained to reap these benefits varies widely between comorbidities. Downsides of weight loss that is too rapid and/or extreme may occur, as in the increased risk of gallbladder disease, the presence of excess residual skin, or deterioration in liver histology. Uncertainty also remains about the potential benefit or harm of intentional weight loss on patients presenting with some chronic diseases and on overall mortality. Clearly, well- controlled prospective studies are needed to better understand the natural history of obesity and the impact of weight-management interventions on morbidity, quality of life, and mortality in people living with obesity.”
The is much left to be done and answering some of these questions will become progressively easier as better treatments for obesity become available.
While the health benefits associated with intentional weight loss for some complications of obesity (such as elevated lipids and diabetes) are well documented, high-quality studies to back many other potential health benefits are harder to find.
Just how well (or poorly) the putative health benefits of long-term intentional weight loss are documented for each of the many conditions associated with obesity, is now detailed in a comprehensive review of the literature that we just published in the Annual Reviews of Nutrition.
The 40 page long review, which includes almost 250 relevant publications, supports the following main findings:
- Defining and assessing clinically relevant obesity and weight change are challenging tasks. In a given individual, there is often little relationship between the magnitude of obesity and measures of health.
- Despite its modest effect on long-term weight loss, behavioral modifications thatimprove eating behaviors and increase physical activity constitute a cornerstone for integral and sustainable weight management.
- Intentional weight loss is associated with a clinically relevant reduction in blood pressure, improvement in cardiac function, and reduction in cardiovascular events. The duration and magnitude of weight change required to achieve a significant benefit are still unclear.
- In individuals with impaired glucose metabolism at any stage, intentional weight loss achieved by any means is associated with a proportional reduction in T2DM prevalence, severity, and progression.
- Intentional weight loss is consistently associated with a clinically relevant reduction in triglycerides and increase in HDL cholesterol. The effects of weight loss on LDL cholesterol are less consistent.
- Overall, nonalcoholic fatty liver disease is commonly associated with excess weight and can show marked improvement with behavioral, pharmacological, and/or surgical weight loss. Very rapid weight loss, however, may worsen liver histology in some patients. Simi- larly, gallbladder disease is not only common in patients presenting with obesity but also highly prevalent after intentional weight loss.
- Obesity is widely recognized as a key modifiable risk factor for osteoarthritis, with sig- nificant improvements in pain and function reported with weight loss.
- Obstructive sleep apnea and obesity hypoventilation syndrome tend to improve with moderate weight loss; however, complete resolution is not common and is related to very significant weight loss.
- Asthma and COPD are clearly associated with obesity. Sustained weight loss seems to be associated with a significant improvement in asthma symptoms. Data for COPD are rather limited.
- Pregnant women who under go bariatric surgery seem to be less likely to present obstetric complications such as gestational diabetes, preeclampsia, and macrosomia.
- Data on weight loss and suicide are controversial. Caution may be in order when con- sidering bariatric surgery in patients with a history of suicide ideation or attempt.
- Data suggest that long-term weight loss is associated with an improvement in health- related quality of life. The amount of weight loss required to achieve a significant change, however, remains controversial.
However, there are many other issues where putative benefits of intentional weight loss remain even less clear than with the above.
For many conditions we will likely not know the long-term benefits of obesity treatments till better treatments become available and are tested in affected individuals.
Of all the complications of obesity, diabetes appears to be most sensitive to changes in body weight. Thus, it makes perfect sense for anyone involved in the care of patients living with diabetes to familiarize themselves with the basics of obesity management.
This is probably why I was invited by the Taiwanese Association of Diabetes Educators this weekend to present a plenary talk on the 5As of Obesity Management at their annual meeting, which draws over 3,000 nurses, dietitians, pharmacists and physicians from across Taiwan.
Judging by the interest in the topic, the (surprisingly?) many questions and the number of folks who came up to me after my talk with additional questions – interest in this topic is as big as anywhere else.
Indeed, the importance of obesity in Taiwan may not be readily appreciated by simply looking at the population, who all appear rather slender compared to what we may be used to in Western countries – but remember obesity here is defined as a BMI or just 27 and many obesity related health problems in Asians occur at much lower body weights than in Caucasians.
This week, the New England Journal of Medicine publishes the results of the SCALE Trial, a 56-week randomised controlled trial of liraglutide 3.0 mg vs. placebo (both groups got advice on diet and exercise), on weight loss and other metabolic variables.
The study, that enrolled about 3,700 subjects (70% of who completed the trial), showed greater clinically relevant weight loss in participants treated with liraglutide than with placebo.
Overall, at 56 weeks,
– 2 in 3 individuals on liraglutide achieved a 5% weight loss (compared to 1 in 4 on placebo).
– 1 in 3 individuals on liraglutide achieved a 10% weight loss (compared to 1 in 10 on placebo).
– 1 in 6 individuals on liraglutide achieved a 15% weight loss (compared to fewer than 1 in 20 on placebo).
The adverse effect profile was as expected from a GLP-1 analogue (mainly gastrointestinal and gall bladder related issues).
While liraglutide 3.o mg has now been approved as an anti-obesity agent in the US, Canada and Europe, its key downsides will likely be cost and the fact that it consists of a once-daily injection.
Obviously, as with any obesity treatment, discontinuation will likely result in weight regain (which is not unexpected, given that obesity, once established, becomes a chronic disease).
While in the US, where there are now 4 novel prescription medications for obesity, liraglutide 3.o mg will be the only novel anti-obesity drug available in Canada – a rather sorry state of affairs for those who need medical treatment for this condition.
Where exactly liraglutide will establish itself in the treatment of obesity in clinical practice remains to be seen (time will tell) – but for some patients at least (especially the high-responders), it will hopefully offer a useful adjunct to behavioural treatments.
Disclaimer: I have received honoraria for consulting and speaking from Novo Nordisk, the makers of liraglutide